• Journal of Oral Medicine and Pain
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• v.23 no.2
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• pp.193-209
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• 1998

In identifying bodies that are severely decayed or damaged, methods using fingerprints and various biochemical tests are known to have its limits. To overcome this, forensic odontological method which is based on the analysis of the cranium, tooth and dental restoration is used to enhance the accuracey of individual identification. For this reason, I have come to analysis of the dental materials that exists between the teeth that is perceived to have been previously restored and the one adjacent to it. By analyzing the constituents of gold crown-restored, non-precious metal-restored, gold inlay-restored and amalgam -restored teeth, and adjacent teeth using EDX(energy dispersive X-ray microanalysis) which was invented to analyze very small amount of elements, the nature of the restoration could be predicted and the results obtained were as follows. 1. Some of constitute of gold alloy was extracted from residual cement of gold crown restoration, but that was not extracted from the restored tooth and the one adjacent to it. 2. Some of constituents of non-precious metal alloy was extracted both in the residual cement on the tooth with no-precious metal restoration and in the tooth with the restoration itself. However, none of its constituents were found in the tooth adjacent to it. 3. Some of constituents of gold alloy were found in the residual cement of gold inlay, but they were not found in the restored tooth and the adjacent tooth. 4. Some of constituents of amalgam alloy were found both in tooth restored with amalgam and in the adjacent tooth. From the results obtained above, it is possible to utilize the data obtained from analyizing residual dental materials in a more effective way. This data compensates for the lost data due to any harm done to the restorations prior to individual identification and further enhances the accuracy. Therefore, it could be concluded that this process of analyzing residual dental materials could be beneficial to individual identification in the area of forensic odontoldogy.

• Journal of Technologic Dentistry
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• v.40 no.2
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• pp.63-69
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• 2018

Purpose: The purpose of this study is to investigate the non-precious metal core materials used in the dental laboratory to fabricate the implant superstructure by CAD / CAM method. And to observe and compare the morphology and distribution of the osteoblasts in relation to implant osseointegration. Methods: In this study, the mandibular right first molar tooth model was selected as an international standard to produce a single core. Using this model, the impression was made with the silicone rubber, the tooth model was scanned, and a single core was designed and 5-axis milling was performed. The materials used were Cobalt-Chromium and Nickel-Chromium, and the cores for dental implant top structures were fabricated according to the procedures of the dental labs. After the fabrication, the marginal area of the core was separated and cell culture experiment was performed. The osteoblast cells used MC3T3-E1, which is currently widely used. For morphological analysis of osteoblasts, cells were posttreated and observed using CLSM (Confocal Laser Scanning Microscope) and compared. Results: The cell adhesion behavior of the specimen surface measured by CLSM was uniformly distributed in specimen A (Cobalt-Chromium) than in specimen B (Nickel-Chromium). The distribution and changes of the cells were different in the two specimens. Conclusion : It is possible to confirm that specimen A (Cobalt-Chromium) is suitable for the living body through adhesion and proliferation of osteoblasts related to implant osseointegration in the non-precious metal superstructure used after implantation. It is considered that it is preferable to use Co-Cr when fabricating the superstructure.

• Proceedings of the Membrane Society of Korea Conference
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• 1994.10a
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• pp.8-11
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• 1994

Disposal of hazardous ions in the aqueous streams is a significant industrial waste problem.. Waste streams from electronics, electroplating, and photographic industries contain metal ions such as copper, nickel, zinc, chromium(IV), cadmium, aluminum, silver, and gold, amongst others in various aqueous solutions such as sulfates, chlorides, fluorocarbons, and cyanides. Typical plating solutions having similar compositions are listed in Table 1. Spent process streams in catalyst manufacturing facilities also contain precious metals such as Ag, Pt, and Pd. Developing an effective recovery process of these metal ions for reuse is important.

• Korean Chemical Engineering Research
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• v.46 no.4
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• pp.806-812
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• 2008

The ammonia decomposition reaction has been of increasing interest as a means of treating ammonia in flue gas in the presence of precious metal catalyst. Various catalysts, $Pt-Rh/Al_2O_3$, $Pt-Rh/TiO_2$, $Pt-Rh/ZrO_2$, $Pt-Pd/Al_2O_3$, $Pd-Rh/Al_2O_3$, $Pd-Rh/TiO_2$, $Pd-Rh/ZrO_2$, $Pt-Pd-Rh/Al_2O_3$, $Pd/Ga-Al_2O_3$, $Rh/Ga-Al_2O_3$, and Ru/Ga-$Al_2O_3$, were synthesized by using excess wet impregnation method. Using a homemade 1/4" reactor at $10,000{\sim}50,000hr^{-1}$ of space velocity in the presence of precious metal catalyst ammonia decomposition reactions were carried out to investigate the catalyst activity. The inlet ammonia concentration was maintained at 2,000 ppm, with an air balance. Both $T_{50}$ and $T_{90}$, defined as the temperatures where 50% and 90% of ammonia, respectively, are converted, decreased significantly when alumina-supported catalysts were applied. In terms of catalytic performance on the ammonia conversion in the presence of hydrogen sulfide, $Pt-Rh/Al_2O_3$ catalyst showed no effect on the poisoning caused by hydrogen sulfide. These results indicate that platinum-rhodium bimetallic catalyst is a useful catalyst for ammonia decomposition.

• Environmental Engineering Research
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• v.18 no.3
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• pp.145-150
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• 2013

Optimal preparation guidelines of a cathode catalyst layer by non-precious metal catalysts were evaluated based on electrochemical performance in single-chamber microbial fuel cells (MFCs). Experiments for catalyst loading rate revealed that iron(II) phthalocyanine (FePc) can be a promising alternative, comparable to platinum (Pt) and cobalt tetramethoxyphenylporphyrin (CoTMPP), including effects of substrate concentration. Results showed that using an optimal FePc loading of $1mg/cm^2$ was equivalent to a Pt loading of $0.35mg/cm^2$ on the basis of maximum power density. Given higher loading rates or substrate concentrations, FePc proved to be a better alternative for Pt than CoTMPP. Under the optimal loading rate, it was further revealed that 40 wt% of FePc to carbon support allowed for the best power generation. These results suggest that proper control of the non-precious metal catalyst layer and substrate concentration are highly interrelated, and reveal how those combinations promote the economic power generation of single-chamber MFCs.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.5
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• pp.582-593
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• 2002

Metal materials have been used in the clothing design on the spirit of ingenious experiment by fashion designers, and they have been put to practical use by several designers who work out a scheme of popular fashion merchandise. This current starting from the 1960s was weakened in the 1980s, but it was appeared with various shapes of metal materials in the 1990s due to a popularity of techno/cyber fashion. Recently, textile engineering technology causes to develop new-materials which are practical and sanitary. The development of fashionable metal materials brings about the popularization of fashion with metal materials, and it induces that mainstream of modem fashion has been changed into designers of pursuing the spirit of ingenious experiment. This study examines the formative characteristics of metal materials that are based on the spirit of ingenious experiment. As a result, it is evaluated that the formative of metal materials shown in modern fashion is futurism, visual concentration, avast-garde, resistance, precious.

• Journal of Technologic Dentistry
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• v.7 no.1
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• pp.19-25
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• 1985

In oder to compare and measure bond strength of ceramometal system with use of ceramco porcelain powder including SnO2 and uni metal, Rexillium III, Vera Bond as non precious alloys manufactured for porecelain-metal restorations. Total 24 test sample were constructed. All Test sample were measured with a Mitutoyo micrometer graduated to 0.01mm. It is as follows measured of thickness 3.3mm(metal : 1.1mm, porcelain: 2.2mm), width 12mm, length 30mm(porcelain 12mm x 12mm), Compared maximum bending stress test. The results obtained were as follows: 1. Bond strength of each metal with ceramco porcelain powder showed statistical significance.(P<0.05) 2. Vera Bond and uni metal, uni metal and Rexillium III revealed no statistical Significance.(P>0.05) Vera Bond and Rexillium III showed statistical significance.(P<0.05) 3. The order of maximum bending stress was Rexillium III, uni metal, vera Bond. The order of bond strength ratio making bending stress was Vera bond, uni metal, Rexillium III.

• Journal of dental hygiene science
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• v.9 no.4
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• pp.405-412
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• 2009

The purpose of this study investigated the effect of Au coating on adhesion between porcelain matrix and metal substructure interface. Titanium, Ni-Cr alloy and Co-Cr alloy are well known as proper metal for the dental restorations. The success of a porcelain fused to metal (PFM) restoration depends upon the quality of the porcelain-metal bond. However, adhesion between dental alloys and porcelain is related to diffusion of oxygen during ceramic firing. The excessive oxidized layers make hard adhesion between dental alloy and ceramic. Ni-Cr and Co-Cr specimens were divided into test and a control group and Titanium specimens were divided into three test groups and a control group. Each group had 20 specimens. The adhesion characteristics of porcelain and metal with Au coating layer and without Au coating layer were observed with scanning electron microscopy(SEM). The adhesion was evaluated by a biaxial flexure test and volume fraction of adherent porcelain was determined by SEM/EDS analysis. Result of this study suggest that Au coating layer is effective barrier to diffuse oxide layer completely protect non-precious alloys from oxidation during the porcelain firing. The SEM photomicrographs of cross-section specimens showed a smooth interface between Au coating layer and metals and porcelain which suggested proper chemical bonding, and no gap, porosity were observed. The mode of failure was mainly adhesive for Ti tested specimens, but mixed failures with adhesive and cohesive were observed in Ni-Cr and Co-Cr specimens. The adhesion between non-precious metals and porcelain would not be improved by Au coating agent. However, It is suggested that the continuous study is required further investigation and development.

• Economic and Environmental Geology
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• v.36 no.4
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• pp.269-274
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• 2003

This study, one of the projects for investigation of the precious metal deposits of the Circum-Pacific Ocean coon-tries, was performed in a gem field of Pailling, Cambodia, in which there are numbers of undeveloped mineral resources. The gem fields in the Pailling area are typically distributed in the laterite, lying on of weathered basalts. The gem grade of corundum is low in the surface soil horizon(less than 1 m in depth), but is higher in the subsurface. Occurrence and genetic environment of the precious stone are not concerned in the soils. A Precious stone that is already made from at the least upper part of volcanic rocks is produced in large quantities to undergoing to weathering of the rocks. A precious stone is made from upper part of the formation under the high temperature when volcano is vomiting or after vomiting. and/or made from between the formation under the high temperature when other volcano is vomiting. Volcanic rocks including precious stone are a little different from other volcanic rocks when volcano is vomiting, but chemical composition of rocks is not far different from other volcanic rocks.

• The Journal of the Korean dental association
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• v.16 no.2 s.105
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• pp.129-137
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• 1978